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On 17 July this year National Grid UK and Element Power of Ireland announced a 3000MW wind power project. The wind generators would be sited in the Irish Midlands. The output would be transmitted direct to the UK, i.e. without connection to Eirgrid. The complementary gas turbines associated with the wind generators would be sited in the UK and would not form part of the project.

I fail to see what the benefits are of this arrangement. Am I missing something?

Benefits -
1 a significant contribution to low carbon energy
2 increases the geographical spread of wind sourced power which improves the overall diversity
3 job creation in Ireland for construction and O&M

Negatives -
1 I'm not seeing anything too obvious (though I accept I may be guilty of some small prejudice).

It'll be interesting to see whether this generation will class as "Onshore" or "Offshore" wind. Whichever, my guess is that it'll be a lot cheaper than the £165/MWh headline figure that EDF are looking for for new nuclear generation @ Hinkley Point (ie excluding the underwriting of decommissioning costs) - so perhaps we might log this as Benefit #4.

Thank you Donald and Jonno,
There isobviously much more to this subject than meets the eye. Obviously the Greenwire project is there to export Irish wind-generated energy to the UK. However in load flow studies published by NGC, the Eirgrid interconnector from Deeside is shown exporting power from the UK to Ireland. Sounds like a long road for a short cut.

Thank you Donald and Jonno,
There isobviously much more to this subject than meets the eye. Obviously the Greenwire project is there to export Irish wind-generated energy to the UK. However in load flow studies published by NGC, the Eirgrid interconnector from Deeside is shown exporting power from the UK to Ireland. Sounds like a long road for a short cut.

No doubt there will be more to this than meets the eye, and I do not know the details. One suspicion would be that while the site may be perfect for a 3GW wind farm, the wind penetration in Ireland is already quite high and maintaining system inertia/stability on that system might be impossible if you just throw on another 3GW of wind just now, since, presently, there is no requirement for these turbines to provide inertial response. Research is ongoing but to my knowledge, inertial responses from turbines are not yet implemented on any commercial machines. Therefore, connecting it to the much larger UK grid is probably more feasible in the short term from system stability standpoints.

That said, this project will clearly include the cost of a long distance point-point HVDC link at 3GW capacity, and you can't help feeling that such a piece of hardware could be more usefully used to link the 2 whole networks directly (as well as allowing the windfarm build), allowing bidirectional flows and enhanced stability for both power networks. That would be the bit I wouldn't understand, unless the financing for the HVDC link is easier if it is directly linked to a renewable scheme with ROCs/LEC incentives, than if it is built more as transmission infrastucture, which doesn't get ROCs or LEC incentives???

Maybe that is the cunning longterm plan? Notionally assign the HVDC link to the windfarm only initially to link it to incentivised schemes, but later reconnect it as UK-Eire network infrastructure?

If the WF is classed as Offshore (which I believe is most probable), then I think the rules will require that the grid-connection infrastructure is sold to an Offshore Transmission Operator (OFTO). I believe that the OFTO could subsequently use the assets for "secondary" purposes - perhaps someone with a greater understanding of the Commercial/ Regulatory issues could contribute some clarification.

Would this work? The Greenwire system sources all its energy from a group of windfarms, and nowhere else. So, when that energy reaches the UK system it is clearly eligible for ROCs of some kind. If 500MW of that is now sent from Pentir to Deeside, and returned to Ireland using the Eirgrid East West interconnector, it would no longer qualify for the Irish equivalent of ROCs as it has clearly been mixed with non-green energy.

Suppose now that a link were made between Greenwire and Eirgrid. would it now be technically possible to have the same energy going round and round, collecting ROC money as it passes into Wales? I'm pretty sure you couldn't do it with an ac system, but with a system containing two dc links, I think it might work.

The point I am really trying to make is that, if this Irish based source of green energy is to qualify for UK ROC income, we must be sure always that Greenwire is supplied only by green generation.

I think we need to take it with a pinch of salt as it's only a proposal and not yet built, on the surface though it appears to be a classic example of well meaning but fragmented policies resulting in unintended consequences.
We have governments pushing for better connected energy networks and yet the renewable support schemes remain national in focus and act as a barrier, or in this example throw up schemes which meet national requirements but at the expense of inefficient utilisation of assets.
You often see reports talking of the UK becoming a renewable energy exporter and yet as it stands there is no viable scheme which would make UK renewable energy exports competitive, absent subsidy from domestic energy users.

I'm very sure that ROCs will only be paid on renewable generation - I've been involved in providing documentation for Ofgem ROC registration - they (rightly) go to the farthest end of a f*rt to ensure this, especially when there's a separate Aux power supply to the Substation and or diesel standby generator.

If the subsea cable link were to be used for other purposes, including exporting some power to Ireland, I'm sure that supplementary metering would be employed to ensure that the spirit and intergrity of ROCs were maintained.

I think I understand this project better now, thanks to Jonno, Andrew and Donald.
In their TEC list, NGC has the Greenwire project classified as two onshore wind farms, one at 2000MW connected at Pembroke and one at 1000MW connected at Pentir.

The Eirgrid East West Interconnector seems to be undergoing commissioning tests right now. It is a 500MW interconnector between Wales and Ireland described as just the East West Interconnector. Its throughput is now shown on the NETA interconnector page at http://www.bmreports.com/bsp/bsp_home.htm